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Posted

I need some help solving this question... an explaination would be extremly helpful.. thanks

 

Calculate the volume occupied by 0.0950 mol of calcium phosphate at 25oC and 101.3 kPa, given its density at this pressure and temperature is 3.14 g/mL.

Posted

Convert the mass in mols to standard units (grams), then use the fact that density = mass/volume (i.e. volume = mass*density).

Posted

Oh, and that volume will then be in ml, not cm3 or some other volume measurement, because you're working from density units that use ml.

Posted
Oh, and that volume will then be in ml, not cm3[/sup'] or some other volume measurement, because you're working from density units that use ml.

 

A ml is a cm3

Posted

Good point.

 

You wouldn't think I was doing a maths degree at university really, would you :P

 

(my excuse is I haven't looked at anything like that for about 3 years).

Posted

You wouldn't think I was doing a maths degree at university really, would you

 

Yes i would students all have there blonde moments, as I forgot my chemistry calculation the other day.

Posted

Calculate the volume occupied by 0.0950 mol of calcium phosphate at 25oC and 101.3 kPa, given its density at this pressure and temperature is 3.14 g/mL.

 

Do as dave said for the ml/per gram, then use:

 

V = P / nRT

 

Where V = Volume (L or dm-3)

 

P = Pressure use 1 atm, as your 101.3Kpa = 1 atm

 

n = number of moles which you calculated.

 

R = gas constant of 0.0821 J.K.Mol-1

 

and T = temperature, that 25 oc = 298.3 K<<<use the K.

Posted
You wouldn't think I was doing a maths degree at university really' date=' would you [/b']

 

Yes i would students all have there blonde moments, as I forgot my chemistry calculation the other day.

 

as terrible as an interview i went on the other day where i blanked out the simple formula for molality... MOLALITY of all things..... general chem one for god's sake..

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